This invention relates to the field of tubes or cameras having an electron beam emitting source therein, and more particularly to a tube or camera having a cold cathode emitter.
A variety of applications exist for an inexpensive, easily constructed tube or camera having a cold cathode. The attributes of such an electron source are significant. For example, a cold cathode emitter requires no heater to produce an electron beam such as required by a thermionic cathode having a filament heater, hence the power requirements are substantially lower. Also, the cold cathode structure is more rugged since one may eliminate the delicate filament. The cold cathode is capable of very high emission current density while providing an extremely narrow emission velocity distribution. This feature provides a display tube having high brightness capability as well as high resolution. When the cold cathode is employed in combination with a camera tube, the narrow emission velocity distribution produces higher resolution capability. Also, the low energy input segments improve the portability of the necessary voltage source.